The numbers on the wheel are arranged in a specific way so as to make it as random as possible.

Apart from the Red and Black numbers being alternated, next to every number from the series 1 through 18 is a number from the series 19 through 36, except for numbers 5 and 10.

Looking at the wheel you will notice that the numbers 5 and 10 are exactly opposite the 0 slot and here is where the wheel splits in two halves: from 0 to 5 and from 10 to 0, and each half totals 333. This is also true for the double-zero roulette wheel, each half from 0 to 00 totals 333.

Voisin du Zero
22-18-29-7-28-12-35-3-26-0-32-15-19-4-21-2-25
Neighbors of Zero. This bet covers 16 numbers surrounding the zero number on the wheel and which are also neighbours on the table, enabling to place split bets. Examples: 0 and 3, 32 and 35.

Orphans
17-34-6
It's a bet on three specific numbers 6, 34 and 17 that are neighbours on the wheel, but far apart on the layout.

Tiers du Cylindre
27-13-36-11-30-8-23-10-5-24-16-33
It's a bet on a specific group of numbers on a section of the roulette wheel that are paired neighbours on the layout.

Orphelins
1-20-14-31-9
It's a bet on a specific group of numbers on a section of the roulette wheel that are neighbours on the wheel, but apart on the layout.